1. Field of the Invention
The present invention concerns an ultraviolet screening powder and cosmetics and, more in particular, an ultraviolet screening powder having good lubricity and water repellency, as well as cosmetics containing such a powder.
2. Discussion of the Background
Heretofore, an ultraviolet reflecting agent has been mixed into cosmetics with an aim of protecting skins against ultraviolet rays. And, as such ultraviolet reflecting agents, titanium oxide, zinc oxide, cerium oxide and the like have been used.
Titanium oxide has a refractive index of as large as 2.5 and shows a high ultraviolet screening effect (ultraviolet reflecting effect), but involves the problem that cosmetics mixed with titanium oxide are whitened upon application and give no natural feeling of make-up. Further, ultra-fine particles of titanium oxide that cause less scattering in the visible light region have also been used, but they have the problem of being coagulated upon preparation of cosmetics since the grain size is too small, which results in deterioration of the ultraviolet protecting effect of cosmetics mixed therewith. Further, since such titanium oxide as referred-to above has no defined particular shape, it shows poor lubricity upon skin application to bring about a problem with respect to the feeling in use.
Finely particulate zinc oxide and cerium oxide are also difficult to be prevented from being coagulated upon preparation of cosmetics having such an oxide blended therewith, and such cosmetics involve a problem with respect to the feeling upon application.
For improving the feeling in use, it has been proposed, for example, to coat the surfaces of spherical silica beads with titanium oxide (Japanese Patent Application Laid-Open (kokai) No. 57653/'86).
Furthermore, such oxides as described above are highly hydrophilic, and cosmetics having them blended therewith are wetted with water or sweat upon application onto skins, which results in a problem with respect to water repellency which, in turn, results in sweat bleeding, make-up bleeding and the like problems.